[akira2501]

> It makes more heat than that it makes motive power (the thing it is designed to do...).

Sure.. but try running that same engine when it gets too cold, which is why "block heaters" exist and get used in certain parts of the world. The operating temperature of the engine _is_ part of the design criteria.

[jacquesm]

Absolutely, but to get it there it has to work first or you'll have to pump in heat from some other source. Starting a large diesel in sub-zero temps can be quite challenging.